Laetare, Fourth Sunday in Lent March 25, 2001


You’re an Isaac, Not an Ishmael!

Galatians 4:21-23, 28-5:1


145, 159, 399 1-4, 399 5-6

Tell me, ye that desire to be under the law, do ye not hear the law? For it is written, that Abraham had two sons, the one by a bondmaid, the other by a freewoman. But he who was of the bondwoman was born after the flesh; but he of the freewoman was by promise. …Now we, brethren, as Isaac was, are the children of promise. But as then he that was born after the flesh persecuted him that was born after the Spirit, even so it is now. Nevertheless what saith the scripture? Cast out the bondwoman and her son: for the son of the bondwoman shall not be heir with the son of the freewoman. So then, brethren, we are not children of the bondwoman, but of the free. Stand fast therefore in the liberty wherewith Christ hath made us free, and be not entangled again with the yoke of bondage. So far the Holy Word.

In Christ Jesus, Who died to set us free, Dear Fellow Redeemed,

If someone were to ask you how many religions there are in the world, what would you answer? A dozen? Fifty? A hundred? Believe it or not, experts estimate that there are currently over fifteen hundred active religions being practiced somewhere in the world! There are people who worship animals, people who worship the sun, people who worship demons and people who worship their own ancestors. There are polytheistic religions, which teach that there are many different gods. There are pantheistic religions, which teach that god is in everything—every rock, every tree, every ray of sunshine. There are dualistic religions; they believe that there is one god of Good and an equally powerful god of Evil. And then there are just a few monotheistic religions, which teach that there is only one God.

So many different religions in the world—and yet, when it comes to salvation, there are really only two—the religion of the Law, and the religion of the Gospel! Because every religion except one teaches that salvation depends on what you do for yourself. The only exception is Christianity. In true Christianity, salvation rests solely on what Jesus did for you! In our text for today, Paul is warning the Galatian Christians that they’re about to make a big mistake in this matter; they’re on the verge of trading in their wonderful freedom in the Gospel for that old slavery to the Law. He uses an interesting picture to help them see their mistake—the picture of the two sons of Abraham, Isaac and Ishmael. This morning I urge you to follow this picture with me, and heed Paul’s warning, as he reminds you—


  1. Born of God’s promise, not man’s plan.
  2. Heir of eternal life, not a castaway.
  3. Made free by Christ, not enslaved to the Law

Paul wrote this letter to the Christian congregation in the province of Galatia. They had a problem. The congregation had started out well, believing the Gospel Paul preached to them. With joy he told them the Good News that they could be saved eternally by trusting in Jesus Christ alone. But while the Apostle was away preaching in other places, a group of false teachers moved in on the Galatians. They were called the Judaizers.

The Judaizers were teaching that faith in Jesus wasn’t enough. In order to be saved, they said, you had to believe in Jesus AND keep all the laws of Moses: the Ten Commandments, the laws of circumcision, of the Sabbath, of clean and unclean foods, etc. When Paul heard about what was going on, he was inspired by the Holy Ghost to write the Letter to the Galatians.

He was bitterly disappointed in them. “O foolish Galatians!” he said. “Who has bewitched you that you should not obey the truth, before whose eyes Jesus Christ was clearly portrayed among you as crucified?3:1. Paul just couldn’t understand why these people, who had known the freedom of the Gospel, would want to make themselves slaves to the Law again. In our text, he says, “Tell me, ye who desire to be under the law, do ye not hear the law?” To show them just how big a mistake they were making, Paul draws a parable from the Old Testament: For it is written, that Abraham had two sons, the one by a bondmaid, the other by a freewoman. But he who was of the bondwoman was born after the flesh; but he of the freewoman was by promise. …Now we, brethren, as Isaac was, are the children of promise.

You probably know the story of Abraham and Sarah, but let me refresh your memory. God once promised Abraham and Sarah that their descendants would be more numerable than the stars in the heavens. But time passed, they grew old, and still they had no children, because Sarah was barren. After a while, they got tired of waiting for God to come through on His promise, so they came up with their own plan.

Sarah had a slave woman named Hagar. Sarah convinced Abraham to sleep with Hagar, thinking that, if a child was born, she could claim it as her own. So they went through with their sinful scheme. And sure enough, a child was born—a son named Ishmael. Being the son of a slave woman, he himself was legally a slave. As it turns out it really didn’t matter anyway, because soon after that the Lord fulfilled His promise, and the aged Sarah miraculously bore her own son, named Isaac. Now Abraham had two sons. One was Ishmael, the son of the slave woman, the product of sinful human scheming. The other was Isaac, the son of the freewoman, the fulfillment of God’s promise. Isaac was born of God’s promise, not man’s plan.

In this story, Paul finds just the illustration he needs to wake up the foolish Galatians. To each of the believers there he says, Remember—YOU’RE AN ISAAC, NOT AN ISHMAEL! You’re the child of the promise! Paul had to remind them of how they came by their salvation in the first place. Was it something they did? Was it a plan they came up with that saved them from their sins? It was not! In fact, Paul says in another place that the plan God had in store to save mankind from sin was so unbelievable that no one could ever have guessed it, “Eye has not seen, nor ear heard, nor have entered into the heart of man the things which God has prepared for those who love Him.I Cor 2:9. The unguessable plan was unbelievably simple: God would give His own innocent Son in exchange for us sinners!

You too, are an Isaac, not an Ishmael. You are a redeemed child, born of God’s promise in Christ. For some people, though, that’s not good enough. Some people are just like those Galatians—they can’t leave well enough alone. They’re not satisfied with God’s plan unless they can add something of their own to it. Some feel they have to chip in their own good works, cooperate with God; “let God do His part, I’ll do mine.” But that’s not the plan.

I heard a man telling a story on TV. He said he never knew how much his family loved him until he came down with double pneumonia. He was flat on his back for two weeks. He was angry and frustrated because he couldn’t do a thing to help himself; he had to let his family do everything. One day he asked his wife what she was so cheerful about, and she said, “Honey, I almost wish you’d be sick more often—it’s the only time we get a chance to do things for you!”

God’s the same way—all He wants is to do things for us! He wants nothing more than to free us from our sins. He wants to help us out of the sinful mess we’ve made of our lives, and He has the perfect plan to do it. But He can’t save us as long as we keep insisting on saving ourselves. “If (salvation) is by grace,” Paul says, “then it is no longer of works; otherwise grace is no longer grace.Rom 11:6. It’s one or the other—either Isaac or Ishmael. Let’s be Isaacs! Let’s own up to our sins, admit that we’re powerless to help ourselves, and look to the cross of our Savior for forgiveness. He won’t let us down! John says, in His first Epistle, “If we say that we have no sin, we deceive ourselves, and the truth is not in us. If we confess our sins, He is faithful and just to forgive us our sins and to cleanse us from all unrighteousness.I Jn 1:8-9.

Another reason why it’s so important for us to be Isaacs, and not Ishmaels, is because of where they’re headed. The Ishmaels—those who put their trust in the Law—are destined to be eternal castaways from God’s grace. The Isaacs—who trust only in the Gospel of Christ—are heirs of eternal life.

Abraham and Sarah, of course, ran into some trouble because of their sinful plan. Once the son of the promise, Isaac, came on the scene, then Ishmael and his mother inevitably became a source of trouble. Ishmael was jealous of Isaac and persecuted him. In a spiritual sense, Paul says, the same thing’s true today: As then he that was born after the flesh persecuted him that was born after the Spirit, even so it is now. Nevertheless what saith the scripture? Cast out the bondwoman and her son: for the son of the bondwoman shall not be heir with the son of the freewoman.

Even in Paul’s day, the people who were ruled by the Law simply couldn’t stand the Gospel. They attacked Paul for preaching it, beat him up and threw him in prison. The same thing happened when Martin Luther came on the scene in the 16th century. When he preached that salvation lies in Jesus alone, not in good works, the church in Rome did everything it could to get rid of him. Do you think it’s any less true today? Don’t kid yourself! Any true believer who confesses that his salvation comes 100% from Jesus and 0% from himself is eventually going to find himself very unpopular. Don’t let the name “Christian” fool you, either, because there are a whole lot of Ishmaels parading under that name, and precious few Isaacs! And those who are Ishmael’s, those who do rely upon their own good works for salvation—even to the slightest degree!—will taste the bitter results of their mislaid confidence on Judgement Day. “Then will the King say to those on the left hand, ‘Depart from Me, you cursed, into the everlasting fire prepared for the devil and his angels!’Mt 25:41.

Thank God for making you an Isaac—a child of the promise! For if your hope of salvation is laid solely on the cross of Jesus Christ, then there’s absolutely no doubt about your future. You are an heir of eternal life. Jesus paid for your sins on the cross, He put His white robe of righteousness on you, and He’s busy right at this moment getting a place ready for you in the mansions of heaven!

There was an interesting attraction at the State Fair last year. Someone put together a list of “lost bank accounts” from all over the state. Most of the accounts belonged to people who had died long ago, but whose relatives had never claimed the money.—So the money just sat there, sometimes for forty or fifty years, earning interest. Some of the accounts contained tens of thousands of dollars. Anyway, if you could prove you were related to the former owner of one of the accounts, they’d give it to you. Well, not many people could resist at least glancing down the list, on the off-chance that they might be heir to a fortune.

Today the Apostle Paul’s saying to you: If your name is Isaac, then you’re the heir. If you’re a child of the Gospel, then, believe it or not, the fortune belongs to you. Through the faith in Christ that the Holy Spirit has given us, each of us is an Isaac; each of us is immeasurably wealthy—for what price can you put on a peaceful conscience, absolute security in this world and the promise of everlasting life in the next?! So as we follow our Savior’s suffering during this Lenten Season, let’s not forget that we’re the reason He gave up His heavenly throne for the rough wood of a Roman cross. I Corinthians chapter eight: “For you know the grace of our Lord Jesus Christ, that though He was rich, yet for your sakes He became poor, that you through His poverty might become rich!” AMEN.

—Paul Naumann, Pastor

Sermon Preached April 2, 2000
Ascension Lutheran Church, Tacoma WA

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